Pressurized fluids, in particular gases, and particularly preferably compressed air, are required in all areas of industrial and artisanal production, for example as operating energy and process energy. In particular compressed air must be dry, oil-free and clean in order to avoid costly production stoppages. Compressed air is usually produced by compression of air, i.e. a compressor sucks in ambient air. The ambient air can contain pollutants, dirt particles and also moisture in the form of water vapor. The water vapor can condense in an uncontrolled manner in the compressed air and lead to operational disruptions and thus to significant costs. In order to avoid operational disruptions, a pressurized fluid is usually supplied to a device for processing, in order to also satisfy the requirements of the different areas of application, for example the clean room requirements of the food or semiconductor industries.
Devices for drying and filtration of a gas are known in a variety of designs. In one preferred embodiment, such devices are formed as sorption dryers.
Sorption dryers generally serve to remove moisture from a gas and in particular a compressed gas such as compressed air, for example. In the production of compressed air, a compressor sucks in ambient air and compresses it. During the compression process, all components of the sucked in air are concentrated in accordance with the operating overpressure with a simultaneous temperature increase. However, the moisture absorption capacity of the compressed air remains approximately constant. The subsequent cooling thus leads to the saturation of the compressed air with moisture, and each additional cooling leads to the condensation of the excess moisture. Water is formed which can cause rust and corrosion in the compressed air throughout the rest of the compressed air system. It can also lead to ice formation. Rust, corrosion and ice formation lead to high consequential costs in the maintenance stage, to compromised quality, in particular in applications which have high compressed air purity requirements, such as applications in the food industry, the pharmaceutical industry or in semiconductor technology, for example, and to the premature failure of individual components and even to a complete production shutdown. Water and moisture must therefore be removed from the compressed air system.
Known sorption dryers usually have at least two containers as sections of a pipeline of the sorption dryer, in which at least one cartridge is arranged containing a drying agent (sorbent)—often in the form of an accumulation of the granular drying agent. Adsorbent drying agents are often used, with absorbent drying agents also being able to be used. The two containers as sections of the pipeline are connected by means of conduits in parallel to one another and in each case to the inlet of the gas to be dried and the outlet of the dried gas. The flow path of the gas is controlled by means of valves. A control unit realizes the control of the valves. The valve control is designed such that a container is always flowed through by the gas to be dried. The gas is dried in said container by binding of the drying agent contained in the container to the moisture contained in the gas. In this phase this container is thus in a sorption or drying phase. During the sorption phase of the one container, the other container is (usually) flowed through in the opposite direction by a portion of the dried gas in order to dry, i.e., to regenerate, the sorbent saturated during a previous sorption phase. This container is thus in the regeneration phase. If the sorbent is dried without an external supply of thermal energy, i.e. only by means of a partial flow of the previously dried gas, this is a so-called cold regeneration. After a predetermined period of time which depends on the workload of the sorption dryer, it is necessary to redirect the valves in the supply and discharge lines such that the container which was previously in the sorption phase is regenerated and the container which was previously regenerated is now used for drying the gas.
The warm regeneration of a sorption dryer is also known from the prior art. In this process, the sorption container in the regeneration phase is regenerated by means of air which is heated by a supply of external energy. The air can be either a partial flow of the dried compressed air or ambient air, for example, can also be used. In order to heat the regeneration air in connection with the warm regeneration electrical heating devices are often used.
Furthermore, it is known to install downstream of such sorption dryers or other drying systems other cleaning stages filled with different adsorption agents or catalysts such as activated charcoal, for example, which filter out other undesirable components of the dried gas, such as oil vapor, for example. Adsorption agents and catalysts are used as means for cleaning because they are able to remove other undesirable components of the dried gas, in particular liquid, vaporous or gaseous materials, from the gas. These are to be differentiated from the agents for filtration of the gas also used in the prior art in such devices, whose task is to remove solids, in particular particles, from the gas.
The used drying agent of a sorption dryer can be replaced. For this purpose, the cartridge in which the drying agent is accommodated or contained can be exchanged.